The correct answer is C. came.
The verb “come” is used to describe the action of moving from one place to another. In the sentence “Who came to see me last week?”, the verb “came” is in the past tense. This indicates that the action of coming took place at a specific time in the past, which in this case is last week.
The other options are incorrect because they do not agree with the tense of the sentence. The verb “comes” is in the present tense, which would indicate that the action of coming is happening now. The verb “will come” is in the future tense, which would indicate that the action of coming will happen at a specific time in the future. The verb “has come” is in the present perfect tense, which would indicate that the action of coming has already happened.
In conclusion, the correct answer is C. came.